Plumbing fixtures having an interior lining or coating in order to prevent leaching or stripping of various metals into the water flowing through these fixtures are known. Thus, for example, German published patent application DE OS 35 15 718 describes a water spigot with a mixing and metering valve. In this fixture the interior bore of the water spigot is coated with plastic. This prevents leaching or washing-out of, for example, lead and zinc from brass fixtures or the stripping of copper from copper fixtures into the water. However, this plastic lining is very expensive to apply.
German patent DE PS 14 192 discloses a fixture body which has its interior tin-plated. However, the tin-plated interior is provided only in order to enable later casting of a lead lining on the inside of the metal body which is itself in contact with the liquid flowing therethrough.
German patent DE-PS 22 802 discloses valves, spigots, pump bodies or other machine parts having a protective coating of tin, among other materials, to protect against chemical attack by chemical agents. However, casting cores are inserted into the iron core to be protected which together with the iron core form a casting mold. This casting mold is lined with tin, thus creating a massive cast protective body of tin. Because of the thickness of the protective tin body, it cannot be employed with fixtures having threads.
It is also possible to utilize fixtures comprised of alloys, the components of which are considered to be physiologically safe. For example, bronze as a pure alloy of copper and tin. However, such alloys are relatively expensive.
Lead free brass alloys or alloys which prevent the leaching of tin due to the alloy's components are also known. However, such brass alloys exhibit disadvantageous machining properties such as forming machining tool clogging long chips upon machining.
Bismuth instead of lead can also be added to a brass alloy in order to maintain the requisite machining properties of the alloy. Also, arsenic or antimony can be used to combat so-called "de-zincing". However, the nature of such alloy is changed. This presents difficulties with recycling.
The present invention avoids the aforediscussed disadvantages and provides a plumbing fixture comprised of an inexpensive, conventional brass alloy wherein metals are not leached-out or stripped into the water flowing through the fixture.